Allowing others to continue in their delusions is abuse.
If I don't know you, I'll just let you go on with your life. But I'm not letting friends or family continue with their delusions.
I won't tell them they're wrong, just explore their delusions to hopefully help them come to their own conclusions.
In my family there are mentally ill, genetic disorders and neuro-atypicals. I deal with this all the time. It's challenging. But it's a responsibility we all share in the family.